Core working hours are a fixed time period during which all employees must be present at the workplace or available remotely. They are typically used in combination with flextime and enable a balance between flexibility and reliable collaboration. There is no statutory regulation for core hours – they are determined by the employer, works agreement, or employment contract.

Definition: What Are Core Working Hours?

Core working hours (also known as core time or fixed time) describe a defined period within the workday during which all employees have a mandatory attendance or availability requirement. This period is always shorter than the total daily working time and forms the binding "core" of the workday.

In practice, core working hours typically fall between 9:00 or 9:30 AM and 3:00 PM. During this time, all employees must be on-site or – in the case of remote work – reachable and able to work. Core hours only become significant in combination with flexible working time models such as flextime. They ensure that despite individual flexibility, all team members can work together at certain times.

How Do Core Working Hours Work with Flextime?

Core working hours are a central component of flextime models. While flextime defines the outer framework within which employees may work, core time establishes the mandatory period within this framework.

Start and End Flexibility Periods

A typical flextime model with core working hours consists of three components:

The framework working time (also called operating hours) defines the entire period during which work may generally be performed – for example, from 7:00 AM to 6:00 PM. Within this framework, there is the start flexibility period, the time before core hours when employees can flexibly begin work. After the core time comes the end flexibility period, during which employees can flexibly end their workday.

Practical Example: A Typical Workday

A company establishes the following arrangement:

• Framework working time: 7:00 AM to 6:00 PM
• Start flexibility period: 7:00 AM to 9:30 AM
• Core working hours: 9:30 AM to 3:00 PM
• End flexibility period: 3:00 PM to 6:00 PM

An employee with an 8-hour day can structure their workday from 7:00 AM to 3:30 PM or work from 9:30 AM to 6:00 PM. The key point: they must be present between 9:30 AM and 3:00 PM in any case.

Who Determines Core Working Hours?

The determination of core working hours generally lies with the employer. However, there are important restrictions and co-determination rights that must be observed.

Role of the Works Council (§87 BetrVG)

If a works council exists in the company, it has extensive co-determination rights regarding working time arrangements. According to §87 Para. 1 No. 2 of the German Works Constitution Act (Betriebsverfassungsgesetz – BetrVG), the works council must consent to the introduction of flextime. The co-determination right also includes setting the beginning and end of core working hours as well as the flexible periods.

The employer therefore cannot unilaterally mandate flextime arrangements with core hours but must negotiate these with the works council. The result is typically documented in a works agreement.

Employment Contract and Works Agreement

Without a works council, the employer can introduce core working hours via a company directive. Regulation through individual employment contracts is also possible but rather the exception. In practice, the works agreement is the most common approach, as it creates uniform regulations for all employees and provides legal certainty.

Advantages and Disadvantages of Core Working Hours

The combination of core time and flextime offers various advantages and disadvantages for both employers and employees.

For employers, the central advantage lies in guaranteed availability: during core hours, all team members are accessible, so meetings, client appointments, and coordination can reliably take place. At the same time, the model promotes employee satisfaction and strengthens employer branding, as flexible working hours are among the most sought-after benefits.

For employees, core working hours enable a better work-life balance. Private appointments such as doctor visits or childcare can be more easily integrated into daily life. Early risers can start early, while night owls can begin their day later.

One disadvantage can be the increased coordination effort, as not all employees are present at all times. For some employees, core time may also be perceived as a restriction – particularly compared to trust-based working time, which offers even more flexibility.

Core Working Hours for Part-Time and Remote Work

The application of core working hours requires special attention in certain work models to find practical solutions.

Special Regulations for Part-Time Employees

For part-time employees, regular core hours can be problematic. If a part-time worker only works four hours daily, a five-hour core time does not fit into their working time model.

In practice, there are various solutions: companies can establish shortened core hours for part-time employees, adjusted proportionally to their working time. Alternatively, an exemption from core hours can be agreed upon when daily working time is very short. For part-time employees who work full hours on individual days, the regular core time applies on those days.

Core Hours in Remote Work

Core working hours also apply in home office and hybrid working models. The difference: instead of physical presence in the office, employees must be digitally reachable and able to work during core hours.

This means specifically: employees must be reachable via email, telephone, or messenger services and able to participate in virtual meetings. Digital time tracking systems help document compliance with core hours even when working remotely. Since the German Federal Labour Court ruling of September 2022, time recording has been mandatory for all companies anyway.

Core Hours Violation: What Happens with Non-Compliance?

Compliance with core working hours is a contractual obligation. Violations can result in employment law consequences – depending on severity and frequency.

For a one-time violation, a clarifying conversation with the supervisor is typically held first. Repeated violations can lead to a written warning. For persistent or serious violations, termination for behavioral reasons is also possible.

Important to know: overtime on other days does not compensate for a core hours violation. The attendance requirement during core time remains regardless of the working time account. Companies therefore frequently use time tracking systems that automatically issue a warning for entries made during core time.

Frequently Asked Questions About Core Working Hours

What are core working hours?

Core working hours are a fixed period with mandatory attendance or availability for all employees. They are typically used in combination with flextime and usually fall between 9:00 or 9:30 AM and 3:00 PM. Outside of core hours, employees can flexibly adjust their start and end times.

Are core working hours legally regulated?

No, there is no explicit statutory regulation for core working hours. The German Working Hours Act (Arbeitszeitgesetz – ArbZG) only regulates maximum working time and break times. Core hours are determined by the employer – with co-determination from the works council if one exists, according to §87 BetrVG.

How long should core working hours be?

There is no legal requirement for duration. In practice, core time usually comprises four to six hours, for example from 9:30 AM to 3:00 PM. It must be shorter than the daily working time to allow for flextime periods. For an 8-hour day, core time of maximum six hours is recommended.

Do core working hours apply in home office?

Yes, core working hours also apply when working from home. Employees must be reachable and available during core time – via telephone, email, or messenger services. Time tracking systems help document working hours even with mobile work.

How do core working hours work for part-time employees?

For full workdays, the same core hours apply to part-time employees as to full-time staff. For shortened days, individual arrangements are possible: proportionally reduced core time or complete exemption for very short daily working hours.

What happens with a core hours violation?

A violation of core working hours is a breach of contractual obligations. One-time violations usually lead to a conversation with supervisors. Repeated violations may result in a written warning; persistent violations can lead to termination for behavioral reasons. Overtime does not compensate for core hours violations.

What is the difference between core time and flextime?

Flextime defines the flexible framework within which work can be performed (e.g., 7:00 AM to 6:00 PM). Core time is the fixed period within flextime with mandatory attendance. The start flexibility period comes before core time, the end flexibility period after.

Who determines core working hours?

Generally, the employer. However, if a works council exists, there is a co-determination right under §87 Para. 1 No. 2 BetrVG. The determination is usually made in a works agreement or company directive, less commonly in individual employment contracts.

Conclusion

Core working hours are a proven instrument for combining flexibility and reliability in everyday work. They allow employees more freedom in planning their working time while giving companies guaranteed attendance periods for meetings and collaboration. For HR professionals, it is important to observe the works council's co-determination rights when introducing core hours and to develop practical solutions for part-time employees and remote workers.

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Sources

• Works Constitution Act (Betriebsverfassungsgesetz – BetrVG) §87. Federal Republic of Germany, 2024. https://www.gesetze-im-internet.de/betrvg/__87.html
• Working Hours Act (Arbeitszeitgesetz – ArbZG). Federal Republic of Germany, 2024. https://www.gesetze-im-internet.de/arbzg/
• Federal Labour Court Ruling on Time Recording (1 ABR 22/21). Bundesarbeitsgericht, 2022. https://www.bundesarbeitsgericht.de/
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